3D‐Printed Hierarchical Nanostructured N‐Co ₂ NiO ₄ NF Electrode for Efficient Concurrent Electrocatalytic Production of Hydrogen and Formate

Abstract Replacing the oxygen evolution reaction with the alternative glycerol electro‐oxidation reaction (GER) provides a promising strategy to enhance the efficiency of hydrogen production via water electrolysis while co‐generating high‐value chemicals. However, obtaining low‐cost and efficient GER electrocatalysts remains a big challenge. Herein, a self‐supported N‐doped Co ₂ NiO ₄ nanoflakes (N‐Co ₂ NiO ₄ NF) is proposed for efficient electrocatalytic oxidation of glycerol to formate. The synergistic effect induced by the interaction of the layered Co ₂ NiO ₄ nanostructures on the 3D‐printed Nickel‐Yttria‐stabilized zirconia (Ni‐YSZ) substrate and the amorphous nitrogen‐doping promotes the anodic GER. The N‐Co ₂ NiO ₄ NF exhibits low potentials of 1.07 and 1.18 V ( vs . RHE) for GER to drive 10 and 50 mA cm ⁻² , respectively. The constituted two‐electrode electrolyzer (N‐Co ₂ NiO ₄ NF//NiS‐Co‐NiP) displays excellent activity that only requires ultralow cell voltages of 1.24 and 1.55 V to afford 10 and 200 mA cm ⁻² , respectively, with a high FE (97%) for formate production and an excellent durability (120 h). This study provides a versatile approach for manufacturing high‐performance Ni‐based electrocatalyst for GER, paving the way for the energy‐saving and environmentally‐friendly co‐production of value‐added chemicals and hydrogen.